the beauty and versatility of wood with the fire safety and
insurance
advantages of non-combustible materials.

The people who developed FRX® wood for interior
applications and the people who developed FRX® shakes and
shingles now offer FRX® wood, fire retardant treated wood that
retains its fire retardancy in outdoor use.

FRX® wood is pressure treated lumber and plywood that is
chemically treated to reduce the spread of flames and provide
tested fire protection for applications directly exposed to
weather.

FRX® wood may be substituted for materials classified as
non-combustible in certain building types designated by the
model building codes and requiring ASTM D-2898 conformance.

FRX® wood combines that beauty and versatility of wood with the
fire safety and
insurance advantages of non-combustible materials.

FIRE PERFORMANCE
The ASTM E-84 tunnel test compares surface burning
characteristics of tested materials to those of asbestos
cement board and untreated red oak lumber. A rating of 0 is
assigned to asbestos cement board and a rating of 100 is
assigned to untreated red oak flooring. Flame spread ratings
of various species of untreated lumber range from 60 to 230.
During this test, smoke emissions are also measured and
ratings are assigned on the same scale. The ratings are
established during the first 10 minutes. Unlike for fire
retardant coatings, however, building codes required that
the test be extended from 10 minutes to 30 minutes and the
flame spread not progress more than 10 1⁄2 feet beyond the
burners and show no evidence of progressive combustion.

Further ASTM E-84 testing is then conducted on material that
has undergone the ASTM D-2898 accelerated weathering test,
also referred to as the "800-inch rain test." FRX® lumber
and plywood maintain flame spread indexes of less than 25,
indicating compliance with building code requirements for
exterior FRTW.

Standard tests for surface burning characteristics of
materials referenced in the model codes as a basis of
acceptance are all essentially the same:

• ASTM E-84 Standard Test Method for Surface Burning
Characteristics of Building Materials.• NFPA 255 - Method of Test Surface Burning Characteristics
of Building Materials is essentially the same as ASTM E-84.• UBC Standard 8-1 Test Method for Surface-Burning
Characteristics of Building Materials is based on Standard
Test Method ASTM E-84.

* Arch Wood Protection does
not recommend the use of FRX® wood in high temperature
interior applications. Dricon® FRTW should be used in these
situations. Contact Arch Wood Protection or visit us online
at www.dricon.com for more information.

FAQ’s

1. Does it meet building codes?Yes. FRX® wood meets the performance requirements of the
model building codes.

2. Can it be painted or stained?
Yes, though not all paints and stains are compatible with
exterior fire retardant treated wood, due to the nature of
the polymer. For an up-to-date listing of acceptable
coatings, click here. Follow the manufacturers'
recommendations for best results. As with untreated lumber,
the surface should be clean and dry. It is also recommended
to apply coating to a sample piece before overall
application to determine compatibility and desired
appearance. Flammability of the finish should be considered
before any application.

3. What species can be treated?
At the present time, Douglas fir, hem-fir, southern yellow
pine and western red cedar.

4. Can FRX wood be used in ground contact?FRX® wood can be used outdoors, but is intended only for
above ground uses.

5. Is there a reduction in strength compared to untreated
wood?Yes. The treating and drying processes cause a reduction in
strength that varies with treatment, species of wood,
applications and specific properties. Adjustment factors for
FRX® wood are shown previously in the Strength Properties
section of this site.

6. What types of fasteners should be used with FRX wood?
Galvanized steel hardware is recommended. Although the FRX®
wood treatment does not increase the corrosion of bare
steel, the galvanizing process provides an extra margin of
safety in wet environments.

7. Can I cut FRX wood?
Yes. Cutting lengths, drilling holes, and light sanding are
permissible. It is not necessary to field-treat cut ends to
maintain the flame spread rating. FRX® lumber should not be
ripped or milled. FRX® plywood can be ripped or cross-cut.